Laminated fluid-jacketed thrust chamber structure



Mam}! 1950 D. c. .EATON ETAL ,926,

LAMINATED FLUID-JACKETED THRUST CHAMBER STRUCTURE Filed March 19. 1957 VIEW "B" ENLARGED nvmvrozes. 0A W0 c. EA 70A/ .4 00/5 F A PA TA l l l United States Patent LAMINATED FLUlD-JACKETED THRUST CHAMBER STRUCTURE David C. Eaton, Paterson, and Louis F. Arata, Whippany, N.J., assignors, by mesne assignments, to Thiokol Chemical Corporation, a corporation of Delaware Application March 19, 1951, Serial No. 647,126

1 Claim. (Cl. 60-35.6)

The invention relates to the jet propulsion art, and has particular reference to the production of a thrust chamher for jet motors or analogous devices such as are used in rockets, guided missiles, and aircraft, in which the chamber wall has curved contour-conforming passages for the circulation of coolant liquid.

The conventional thrust chamber has a convergentdivergent axial nozzle orifice which makes the production of contour-conforming coolant passages a difiicult problem. Due to the impracticability of drilling such devious passages in the chamber wall, other methods have been adopted, such as casting appropriately curved longitudinal tubes in the chamber block, or uniting comparatively thick abutting coaxial rings having axially aligned coolant passages. The latter method possesses the disadvantage that, although substantially identical rings may be used for the wall portions of uniform inside diameter, it is necessary to include specially shaped rings having inclined passages for the convergent-divergent nozzle orifice portion. Such a construction is complicated and very expensive.

It, therefore, is the primary object of our present invention to provide an improved means and method of producing a laminated thrust chamber in accordance with which the entire chamber is built up from stacked thin laminations having straight axial passages formed therein. A significant advantage of this construction is the fact that all laminations for the chamber structure may be punched, cast, or etched, from sheet metal or similar stock. The only different between the several laminations of a chamber-fabricating set lies in the inside and outside diameters and in the relative arrangement of the perforations that make up the coolant p-assages when the laminations are assembled.

Other objects, advantages and features of the invention will become apparent as the following specific description is read in connection with the accompanying drawing, in which:

Fig. 1 is a side elevational view of the thrust chamber in partial longitudinal section;

Fig. 2 is a transverse section on line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary longitudinal section of a portion of one side wall of the nozzle orifice.

Referring now in detail to the drawing, in which like reference characters designate corresponding parts in the several views, it will be observed that our improved thrust chamber is composed of a stack of closely abutting axially aligned annular laminations 11 of equal thickness throughout the length of said chamber. This feature of equal thickness is important,.particularly in the interest of economy, because it means that all of the composite laminations may be stamped or punched from a single sheet of suitable material.

Because it usually is desirable to provide the thrust chamber 10 with a wall 12 of uniform thickness throughout its length and at the same time produce a constricted 2,926,490 Ice 1 Patented Mar. 1, 1960 convergent-divergent nozzle orifice 13 near its exhaust end, all laminations 11 will not have the same inside and outside diameters. Instead, those laminations 11 in the region of nozzle orifice 13 will very in inside and outside diameters to give the orifice its desired longitudinal contour. In other words, the complete stack of laminations 11 is made up of a series in which some are identical and some vary in diametrical dimensions at appropriate locations to alford the desired longitudinal configuration.

In order to jacket the wall 12 of thrust chamber 10 for circulation of a coolant liquid, each lamination 11 is provided by suitable process, such as punching, etching, or casting, with an annular row of perforations 14. For eflicient heat transfer from the hot interior of thrust chamber 10, when in operation, each perforation should be located equidistant from the inner and outer periphery of wall 12. If the thrust chamber should be modified to provide a completely cylindrical outer periphery, i.e. of uniform outside diameter throughout its length, then the perforations in the region of nozzle orifice 13 should be at least equally spaced from the inner periphery of wall 12. This space relation applies regardless of the intended location of any individual lamination in the over-all series. The several perforations of all laminations of the series have their respective axes parallel to the thrust chamber axis, to include those perforations which are located in the region coextensive with the convergent-divergent nozzle orifice. In other words, the side walls of each orifice are perpendicular to the broad faces of the lamination in which the orifice is punched or otherwise produced.

As to the shape or marginal outline of each perforation 14, it may be trapezoidal as shown in Fig. 2, or may be of any other desired form, such as circular. The size of each perforation 14 of the complete series of laminations 11 and the circumferential spacing between the perforations of each lamination must be such that the perforations of any lamination will be in substantially axial registration with the perforations of the next adjoining laminations upon assembly of the series in order to provide the required parallel longitudinal coolant passages 15. In the region of the convergent-divergent nozzle orifice 13, the marginal edges of the registering perforations 14 of abutting laminations 11, which perforations unite to form each coolant passage 15 of the completed thrust chamber 10, are stepped as shown on an enlarged scale in Fig. 3. This stepped arrangement is unavoidable due to the economical mode of producing the orifices in comparatively thin sheet material, but each resulting coolant passage will be of sufficient cross-sec tional area for effective coolant flow and will closely parallel the orifice contour.

The method of producing our improved laminated thrust chamber consists in four principal steps, viz: (1), fabrication of the complete series of matching laminations; (2), preparation of the laminations for joining; (3), assembly of the laminations; and (4), joining the assembled laminations.

In Step 1 the several laminations 11 of related diametrical dimensions and perforation arrangements are fabricated by suitable process such as by punching from sheet material, casting, or etching. The particular material used may be either a suitable metal or refractory material.

In Step 2, the laminations of the series are prepared for the selected method of joining, which includes suitable cleaning and surface preparation. For instance, if brazing is to be the method employed, their meeting surfaces will be coated with braze metal. An-alternative methlod is by dipping the laminations in liquid braze meta.

Step 3 comprises stacking the series of laminations in the proper order of diametrical dimensions to produce the desired internal contour having the convergent-divergent nozzle orifice structure; arranging the laminations rotationally to obtain proper longitudinal.registration of the perforations that form the longitudinal coolantpassages; and fixturing the assembled laminations to maintain this arrangement during the joining step.

In Step 4, abutting laminations are united permanentlyin an integral structure by the chosen method, such as by welding, furnace brazing, or by dip braze.

After the complete thrust chamber has resulted from these four steps, it may be finished by the addition of welded supports (not shown). If it be'desired to provide the coolant passages 15 with-smooth walls to facilitate liquid circulation, that may be accomplished by the use of suitable tools to remove the stepped sharp corners where adjacent laminations slightly overlap in the nozzle orifice section. However, the existence of sharpcorners may be favorable to heat transfer.

While there have been shown and described and pointed out the fundamental novel features of this invention as applied to a single structural embodiment and method of production, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and its operation in the steps of the method may be made by those skilled in the art without departing from the spirit of the invention. It

is the intention, therefore, to be limited only as indicated by the scope of the following claim.

We claim:

A thrust chamber for a jet motor having a convergent-divergent nozzle orifice and longitudinal coolant passages in its side wall conforming in axial contour to said orifice, said thrust chamber comprising: a stack of abutting coaxialannular laminations produced from thin sheet material and being of equal thickness and of respective inside and outside diameters appropriately graduat ed axially to provide the desired internal longitudinal configuration, said laminations being provided with annular rows of 'circumferentially equally spaced axially registering perforations of appropriate sizes and spacing in a direction circumferential with respect to the thrust chamber to form the coolant passages, the perforations of all laminations being equidisant from the inner peripheral face of the chamber structure and having their axes parallel to the thrust chamber axis to include the perforations in the region coextensive with the convergent-divergent nozzle orifice; and means to join the stacked laminations in an integral structure.

References Cited in the file of thispatent I UNITED STATES PATENTS, 2,125,970 

